Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 1525

July 20, 20126 parishes in Louisiana; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2012, 7:47 PM CDT for 6 parishes in Louisiana; 6 counties in Texas. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jul 20, 2012, 7:47 PM CDT (00:47 UTC)
Expired: Jul 20, 2012, 9:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Jefferson Davis Parish, LA, Vernon Parish, LA, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 64 km from the middle of the area, began a volume at 00:47 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 0.8 hours before the alert went out and 65 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 2837 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1302 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 62 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 21, 12:45 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 6 more	3 hr
Jul 21, 6:14 PM CDT	Severe Thunderstorm Watch	SPC	Bossier, Caddo, De Soto, Red River, Sabine, Webster	6 hr
Jul 21, 2:06 PM CDT	Mesoscale Discussion	SPC	Andrews, Archer, Armstrong, Bailey, Baylor, Borden and 64 more	2 hr
Jul 21, 5:37 PM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Austin, Bastrop, Brazos, Burleson and 31 more	83 min

Nearby

Mesoscale Discussions in Louisiana, 2012 Mesoscale Discussions in Texas, 2012 Every mesoscale discussion in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.